Final answer:
cos(θ) is found using the Pythagorean identity, and the correct value is 20/29 after calculating, which is not listed in the provided options.
Step-by-step explanation:
The question is asking for the value of cos(θ) given that sin(θ) = 21/29. Using the Pythagorean identity for trigonometry, which states that sin2(θ) + cos2(θ) = 1, we can find the value of cos(θ). First, we find sin2(θ) = (21/29)2, and then we use the identity to solve for cos2(θ) = 1 - sin2(θ). Finally, we take the positive square root (since we're not given information about which quadrant θ is in) to find cos(θ). Calculation shows that cos(θ) is 20/29, which was none of the options provided. Hence, it's likely a typo in the given options.